In the use of refrigerants, such as Freon and the like, it has been common to provide quick disconnect couplings for connecting and disconnecting lines in the systems and particularly lines for servicing a refrigeration system. It is desirable that such couplings be operable to cause substantially no refrigerant to enter the atmosphere.
More recently, it has been recommended that instead of the conventional refrigerant such as Freon other refrigerants which are more environmentally acceptable be utilized. One such refrigerant is known as HFC-134A. In order to prevent prior types of refrigerant from being used in such systems, the industry has adopted a standard for the fitting on which the coupling is to be mounted and specified that the fitting not use threads, as in prior couplings, but rather to use an annular groove or shoulder.
Another problem with respect to prior art couplings, is that in the process of disconnecting the couplings after service, the force of refrigerant under pressure can, under certain circumstances, provide a substantial force that can cause the operator to lose their grasp with the coupling and possibly injure the operator.
Accordingly, among the objectives of the present invention are provide a quick disconnect coupling which is specially adaptable for use with the new refrigerant such as HFC-134A; which is operable to first engage the fitment with which it is used and thereafter to open communication with the fitment and the hose or other device which is being connected by the coupling.
In accordance with the invention, a quick disconnect coupling for unthreaded refrigerant fitments comprising an outer housing, an inner housing over which the outer housing is telescoped and a spring loaded plunger mounted for sliding movement within the inner housing. The inner housing has a circumferential portion at one end that is adapted to telescope over a valve fitting on a refrigeration system which has an annular groove and a one way valve normally closing the fitting. The plunger is normally out of engagement with the one way valve when the coupling is first placed in position o the fitment. A plurality of groove engaging elements in the form of balls are circumferentially provided on the one end of the inner housing for movement radially into and out of engagement with the groove on the fitment. The outer housing is provided with a circumferential portion normally overlying the balls and is movable to bring a ramp portion into engagement with the balls and thereby force the balls into the groove of the fitment. Interengaging portions between the outer housing and inner housing operate upon rotation of the inner housing relative to the outer housing to move the outer housing axially relative to the inner housing causing the ramp portion to engage the balls and move them into the grooves. Further rotation of the inner housing relative to the inner housing causes the outer housing to move axially a further distance to permit the spring loaded plunger to move axially toward the one way valve in the fitting and open the one way valve as well as move the inner housing axially away from a seat in the outer housing and provide communication to the exterior at the other end of the outer housing.